Modulation method, modulation apparatus using the same, demodulation method, and demodulation apparatus using the same

Abstract

Disclosed is a modulation method for modulating n-bit data (n=p+q+r). The modulation method includes forming a time difference between a data impulse and a sync impulse to correspond to p-bit data, modulating the amplitude of the sync impulse to correspond to q-bit data and modulating the amplitude of the data impulse to correspond to r-bit data, and combining the sync impulse and the data impulse. As an example, n may be equal to p+q+r.

What is claimed is: 
     
       1. A modulation method for modulating n-bit data, the modulation method comprising:
 forming a time difference between a sync impulse and a data impulse to correspond to p-bit data; 
 modulating the amplitude of the sync impulse to correspond to q-bit data and modulating the amplitude of the data impulse to correspond to r-bit data; and 
 combining the sync impulse and the data impulse, 
 wherein the forming of a time difference comprises: 
 receiving a clock signal and delaying the clock signal to correspond to the p-bit data to form a data edge; 
 forming a sync window corresponding to an edge of the clock signal and a data window corresponding to the data edge; and 
 forming the sync impulse corresponding to the sync window and the data impulse corresponding to the data window. 
 
     
     
       2. The modulation method of  claim 1 , wherein the modulating of the amplitude of the sync impulse to correspond to q-bit data comprises:
 receiving the sync window; 
 decoding the q-bit data to provide the decoded q-bit data to a push-pull stage; and 
 forming, by the push-pull stage using current corresponding to the decoding result, a sync impulse with an amplitude corresponding to the q-bit data. 
 
     
     
       3. The modulation method of  claim 2 , wherein the modulating of the amplitude of the data impulse to correspond to r-bit data comprises:
 receiving the data window; 
 decoding the r-bit data to provide the decoded r-bit data to the push-pull stage; and 
 forming, by the push-pull stage using current corresponding to the decoding result, a data impulse with an amplitude corresponding to the r-bit data. 
 
     
     
       4. A demodulation method comprising:
 down-converting an RF signal to baseband and outputting envelope signals of a pulse; 
 demodulating a time difference between the envelope signals; and 
 demodulating the amplitude of the envelope signals, 
 wherein the demodulating of a time difference comprises:
 comparing the envelope signals to a threshold voltage to form pulses corresponding to the envelope signals; 
 detecting edges of the pulses; and 
 performing time-to-digital conversion for forming digital code corresponding to a time difference between the detected edges of the pulses. 
 
 
     
     
       5. The demodulation method of  claim 4 , wherein the down-converting of an RF signal to baseband is performed by an envelope detector. 
     
     
       6. The demodulation method of  claim 4 , wherein the demodulating of a time difference is performed at a sampling rate higher than a sampling rate at which the time difference is modulated. 
     
     
       7. The demodulation method of  claim 4 , wherein the demodulating of the amplitude comprises:
 detecting a peak of the envelope signals; and 
 forming digital code corresponding to the detected peak. 
 
     
     
       8. The demodulation method of  claim 4 , wherein the demodulating of the amplitude is performed using an analog-to-digital converter with a bit resolution higher than a bit resolution of a digital-to-analog converter for modulating the amplitude. 
     
     
       9. The demodulation method of  claim 4 , wherein the demodulating of a time difference between the envelope signals and the demodulating of the amplitude of the envelope signals are performed at the same time. 
     
     
       10. A modulation apparatus for modulating n-bit data (n is p+q+r), the modulation apparatus comprising:
 a time difference modulation unit configured to form a time difference between a sync impulse and a data impulse to correspond to p-bit data; 
 an impulse amplitude modulation unit configured to modulate the amplitude of the sync impulse to correspond to q-bit data and modulate the amplitude of the data impulse to correspond to r-bit data; and 
 a matching unit configured to combine the modulated sync impulse and the modulated data impulse, 
 wherein the time difference modulation unit comprises: 
 a digital-to-time converter (DTC) configured to receive a clock signal and delay the clock signal to correspond to the p-bit data to form a data edge corresponding to the data impulse; and 
 a window generator configured to receive the data edge, form a data impulse window corresponding to the data edge, and form a sync impulse window corresponding to a reference edge of the clock signal. 
 
     
     
       11. The modulation apparatus of  claim 10 , wherein the impulse amplitude modulation unit comprises:
 a sync impulse generator comprising a push-pull stage configured to receive the sync impulse window and form a sync impulse with an amplitude corresponding to the q-bit data from the sync impulse window; and 
 a data impulse generator comprising a push-pull stage configured to receive the data impulse window and form a data impulse with an amplitude corresponding to the r-bit data from the data impulse window. 
 
     
     
       12. The modulation apparatus of  claim 11 , wherein
 the sync impulse generator and the data impulse generator further comprise a decoder configured to decode provided digital data and output the digital data to the push-pull stage, and 
 the push-pull stage controls the amplitude of the impulse using current corresponding to the decoded data. 
 
     
     
       13. A demodulation apparatus comprising:
 an analog front end configured to down-convert a radio frequency (RF) signal to baseband and output envelope signals; 
 a time difference demodulation path configured to demodulate a time difference between the envelope signals and output data; and 
 an amplitude demodulation path configured to demodulate the amplitude of the envelope signals and output data, 
 wherein the time difference demodulation path comprises:
 a comparator configured to compare the envelope signals to a threshold voltage to form pulses corresponding to the envelope signals; 
 an edge detector configured to detect edges of the pulses; and 
 a time-to-digital converter (TDC) configured to form digital code corresponding to a time difference between the detected edges of the pulses. 
 
 
     
     
       14. The demodulation apparatus of  claim 13 , wherein the analog front end comprises an envelope detector configured to down-convert an RF signal to baseband and detect an envelope of the down-converted signal. 
     
     
       15. The demodulation apparatus of  claim 13 , wherein the time difference demodulation path demodulates the time difference at a sampling rate higher than a sampling rate at which the time difference is modulated. 
     
     
       16. The demodulation apparatus of  claim 13 , wherein the amplitude demodulation path comprises:
 a peak detector configured to detect a peak of the envelope signals; and 
 an analog-to-digital converter (ADC) configured to form digital code corresponding to the detected peak. 
 
     
     
       17. The demodulation apparatus of  claim 13 , wherein the amplitude demodulation path is performed using an ADC with a bit resolution higher than a bit resolution of a digital-to-analog converter for modulating the amplitude.